Attempting to call grow on a spilled SmallVec with a value equal to the current capacity causes it to free the existing data. This performs a double free immediately and may lead to use-after-free on subsequent accesses to the SmallVec contents. An attacker that controls the value passed to grow may exploit this flaw to obtain memory contents or gain remote code execution.
github.com/servo/rust-smallvec
github.com/servo/rust-smallvec/commit/c20cfa8584e649f00dc0767ab6fad63a3f59a296
github.com/servo/rust-smallvec/commit/f96322b9243405cc82701cc73f1b19313b413ab4
github.com/servo/rust-smallvec/issues/148
github.com/servo/rust-smallvec/issues/149
nvd.nist.gov/vuln/detail/CVE-2019-15551
rustsec.org/advisories/RUSTSEC-2019-0009.html